我国油气资源对外进口严重，在保障能源安全方面面临挑战。利用储量丰富的煤炭资源发展清洁高效的热解制油气技术成为目前国家能源的重点研究领域。本文针对常规热解产物收率低、品质差、系统装置易堵塞等问题，以及目前预处理技术存在成本较高、污染环境、效果不够理想等诸多缺点，以西部富油煤为实验对象，利用液氮对富油煤进行低温冷冻预处理，开展快速热解实验，结合BET、SEM、元素分析仪、GC、GCMS等多种检测分析方法，研究热解温度和低温预处理温度对富油煤快速热解产物分布和特性的影响，探索不同原料热解的低温预处理作用，揭示富油煤高低温瞬变下产物生成规律，主要研究结论如下：

在350~900℃的温度区间内，随着热解温度的升高，四种富油煤热解固体半焦产物产率升高，气体产物产率下降，液体产物产率先升高后降低，在500℃时产率达到最大值，产率可达5.3~12.5%。随着热解温度升高，固体半焦中C元素含量上升，半焦热值增高；气体产物中H₂含量上升，CH₄含量先升高后降低，气体热值先升高后降低；富油煤液体产物中，脂肪烃占比随着温度升高趋近于0，多环芳烃占比不断增加，酚类占比降低。富油煤热解碳转化率随着温度升高而不断增大，提高了12.4~37.6%。

在液氮低温预处理下，四种富油煤的焦油产率得到明显提高，且预处理温度与焦油产率呈正相关，升幅可达3.3~51%。热解固体半焦表面结构孔隙增大，C、H元素占比提高，O元素含量占比出现下降，半焦发热量升幅可达1.9~10.6%；对热解气体中CH₄和H₂的释放有促进作用，而对CO₂和CO的释放有抑制作用，气体产物发热量升幅可达0.7~46.9%；富油煤液体产物组分受液氮低温预处理影响明显，禾草沟、小保当和永焦油成分中苯类占比下降，凉水井的苯类含量大幅上升。酚类物质占比出现了降低，降幅可达55.7~59.68%。永顺的多环芳烃增幅达14.22%，而其他三种富油煤多环芳烃降幅达30.91~33.64%。富油煤热解碳转化率经液氮低温预处理增幅可达3.2~38.9%。

在液氮低温预处理下，对比不同原料（富油煤和生物质）的热解产物分布和特性，研究发现富油煤与生物质的液体产率最大增幅分别可达51%和23.73%，富油煤的液体产率低于生物质，减少了9.4~14%；低温预处理有效提高富油煤和生物质的固气产物热值，最大增幅分别可达10.6%和53.3%，富油煤的固气产物热值高于生物质，分别增加了9.39~11.13MJ/kg和8.91~16.65MJ/Nm³；液氮低温预处理后，生物质液体产物中的苯类物质普遍高于富油煤，酚类、多环芳烃类和脂肪烃类都明显少于富油煤，尤其是多环芳烃类和脂肪烃类在生物质液体中的占比趋近于0。

本研究发现，液氮低温预处理有效提高了富油煤热解焦油产率与产物品质，且在不同原料下都存在普遍适用性，为富油煤高效转化利用探索出新途径，对实现我国能源安全战略具有重要理论意义和应用价值。

China faces challenges in ensuring energy security due to its heavy dependence on imported oil and gas resources. The development of clean and efficient technologies for coal pyrolysis to produce oil and gas, utilizing the country’s abundant coal reserves, has become a key research area in national energy development. This paper addresses issues such as low yield and poor quality of conventional pyrolysis products, system clogging, and the drawbacks of current pretreatment technologies, including high cost, environmental pollution, and suboptimal results. Experiments were conducted using tar-rich coal from the western regions, with liquid nitrogen used for cryogenic pretreatment, followed by rapid pyrolysis experiments. Various analytical methods, including BET, SEM, elemental analyzers, GC, and GCMS, were employed to study the effects of pyrolysis and cryogenic pretreatment temperatures on the distribution and characteristics of the products of rapid pyrolysis of tar-rich coal. The study also explored the role of low-temperature pretreatment in different raw material pyrolysis processes, revealing the product formation patterns under high and low-temperature transitions in tar-rich coal. The main conclusions are as follows:

Within the temperature range of 350-900°C, as the pyrolysis temperature increased, the yield of semi-coke solid products from four types of tar-rich coal increased, while the yield of gas products decreased, and the yield of liquid products initially increased and then decreased, reaching a maximum at 500°C with a yield of 5.3-12.5%. As the pyrolysis temperature increased, the carbon content in the semi-coke rose, enhancing its calorific value; the H₂ content in the gas products increased, and the CH₄ content initially rose then declined, with the calorific value of the gas products following a similar pattern; in the liquid products of the tar-rich coal, the proportion of aliphatic hydrocarbons approached zero with rising temperature, the proportion of polycyclic aromatic hydrocarbons continually increased, and the proportion of phenolics decreased. The carbon conversion rate of tar-rich coal pyrolysis increased with rising temperatures, improving by 12.4-37.6%.

Under liquid nitrogen cryogenic pretreatment, the tar yield from four types of tar-rich coal was significantly enhanced, with a positive correlation between pretreatment temperature and tar yield, increasing by 3.3-51%. The surface structure of the pyrolysis semi-coke showed increased porosity, and the proportions of carbon and hydrogen rose while the proportion of oxygen decreased, boosting the calorific value of the semi-coke by 1.9-10.6%; it facilitated the release of CH₄ and H₂ in the pyrolysis gas, but suppressed the release of CO₂ and CO, with the calorific value of the gas products increasing by 0.7-46.9%; the composition of the liquid products from tar-rich coal was significantly affected by liquid nitrogen cryogenic pretreatment, with a decrease in the proportion of benzene in Hechao Gou, Xiaobao Dang, and Yong Jiao oil components, while it significantly increased in Liangshuijing. The proportion of phenolic substances decreased across the board, with a reduction of 55.7-59.68%. The increase in polycyclic aromatic hydrocarbons in Yongshun reached 14.22%, while the other three types of tar-rich coal saw reductions of 30.91-33.64%. The carbon conversion rate of tar-rich coal pyrolysis was increased by 3.2-38.9% through liquid nitrogen cryogenic pretreatment.

Under the preconditioning of cryogenic treatment with liquid nitrogen, a comparison of the distribution and characteristics of pyrolysis products from different feedstocks (tar-rich coal and biomass) revealed that the maximum increase in liquid yield for tar-rich coal and biomass could reach 51% and 23.73%, respectively. The liquid yield from tar-rich coal was found to be 9.4~14% lower than that from biomass. The pretreatment effectively improved the calorific value of the solid and gas products from both tar-rich coal and biomass, with the maximum increases being 10.6% and 53.3%, respectively, and the calorific value of tar-rich coal’s solid and gas products being higher than that of biomass, increasing by 9.39-11.13MJ/kg and 8.91-16.65MJ/Nm³, respectively; after liquid nitrogen cryogenic pretreatment, the proportion of benzene in the biomass liquid products was generally higher than in tar-rich coal, and phenolics, polycyclic aromatic hydrocarbons, and aliphatic hydrocarbons were significantly less in biomass, especially with polycyclic aromatic hydrocarbons and aliphatic hydrocarbons approaching zero.

This study found that liquid nitrogen cryogenic pretreatment effectively enhances the yield and quality of tar from tar-rich coal pyrolysis and is broadly applicable across different raw materials, offering a new pathway for the efficient conversion and utilization of tar-rich coal, with significant theoretical and practical value for achieving China’s energy security strategy.

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